Biomedical Engineering Reference
In-Depth Information
TABLe 20.2
Inluence.of.Nanoscale.Pits.on.Cellular.Adhesion
Adhesion
Modulation
Study
Cell Type
Chemistry
Pitch
Width
Depth
Park.et.al..(2009)
Rat.hematopoietic.
stem.cells
TiO
2
15.nm
15.nm
1.5.μm
Increased.
adhesion.and.
viability
Karuri.et.al..
(2006)
Corneal.epithelial.
cells
Silicone
400.nm
Variable
350.nm
Increased.
adhesion
Hart.et.al..(2007)
Osteoprogenitor.
cells
Poly(carbonate)
300.nm.
Hexagonal.
array
120.nm
100.nm
Decreased.FA.
formation
Dalby.et.al..
(2006a)
h-TERT.ibroblast.
cells
Poly(methyl.
methacrylate)
300.nm.
Hexagonal.
array
120.nm
100.nm
Decreased.focal.
and.ibrillar.
adhesion.
formation
Hajicharalambous.
et.al..(2009)
Corneal.epithelial.
cells
Poly(acrylic.acid)
Variable
100
50.nm
Increased.
adhesion
Lim.et.al..(2007)
Human.fetal.
osteoblastic.cells
Poly(l-lactic.
acid)/pS.blend
Variable
400.nm
45.nm
No.
modiication
Lim.et.al..(2007)
Human.fetal.
osteoblastic.cells
Poly(l-lactic.
acid)/pS.blend
Variable
90.nm
14.nm
Increased.
adhesion
Curtis.et.al..(2004)
Poly(caprolactone) 200.nm 75.nm — Decreased.FA.
formation
Experimentally,.cellular.adhesion.and.focal.adhesion.formation.are.decreased.on.nanopit.arrays.with.x-y.dimen-
sions.>73.nm.and.an.edge-edge.spacing.of.<73.nm..Conversely,.adhesion.is.reported.to.increase.when.topo-
graphical.pits.do.not.meet.or.exceed.these.critical.feature.dimensions.
h-TERT.ibroblast.
cells
(Biggs. et. al.. 2007;. Dalby. et. al.. 2007).. It. seems. that. introducing. a. degree. of. disorder. or.
increasing. the. interpit. area. facilitates. focal. adhesion. formation. and. subsequent. cellular.
spreading.
Highly. ordered. arrays. of. 120.nm. wide. nanopits,. in. both. hexagonal. and. square. con-
formation. patterns,. signiicantly. reduce. cell. adhesion. by. directly. modulating. ilopodial.
activity.(Hart.et.al..2007).and.preventing.focal.adhesion.re-enforcement.(Biggs.et.al..2007),.
indicating. the. ability. of. cellular. populations. to. gather. spatial. and. topographical. signals.
from.nanoscale.pits..Moreover,.it.is.reported.that.focal.adhesion.formation.on.nanoscale.
pit.arrays.occurs.at.the.interpit.region.(Dalby.et.al..2006a;.Biggs.et.al..2008),.suggesting.that.
sites.of.focal.adhesion.can.be.facilitated.or.restricted.by.modifying.the.planar.interpit.area.
(Figure.20.3B)..The.conformation.of.ordered.nanopit.substrates.may.also.dictate.parallel.or.
perpendicular.adhesion.formation.and.perturb.the.radial.peripheral.focal.adhesion.forma-
tion.observed.during.early.cell.spreading.
This.has.been.demonstrated.in.numerous.studies,.whereby.arrays.possessing.a.pit.edge-
edge. spacing. of. <73.nm. reduce. cellular. adhesion.. A. study. by. Lim. et. al.. concluded. that.
greater.cell.adhesion.and.increased.integrin.expression.occur.when.topographic.features.
have. approximately. 10-20.nm. z-axis. dimension. (height. or. depth),. and. that. this. occurs.
despite.topographic.shapes.(protrusion.or.pit).(Lim.et.al..2007)..Also,.this.effect.deterio-
rated.when.nanofeature.z-dimensions.exceed.this.value,.again.indicating.the.perturbing.
effects. of. nanopits. and. pores. on. cell. adhesion. when. >34.nm. (Krasteva. et. al.. 2004;. Lim.
et.al..2007)..Similarly,.the.effects.of.pit.diameter.on.focal.adhesion.formation.were.recently.
demonstrated.in.a.study.by.Park.and.colleagues.with.hollow.TiO
2
.nanotubes..It.was.shown.
